Effect of Solvents on Thermomechanical Properties and Piezoelectric Beta-phase of PVDF-TrFE Films

Co-polymer polyvinylidene fluoride-co-trifluoroethylene (PVDF-TrFE) is a promising piezoelectric material for a range of medical and industrial applications such as tissue engineering, sensors and membrane technics. In this regard, blend electrospinning is an ideal method to produce suitable polymeric nano- and micro-fiber scaffolds or membranes from polymer solutions. Stable electrospinning process is strongly dependent on PVDF-TrFE solution properties. Thus, this study aimed at evaluating the effect of different suitable solvents on physical properties PVDF-TrFE polymer solutions and produced films with different solvent combinations and mixing ratios. The results indicate that solution viscosities range between 5.47 and 37.17 Pa.s. Furthermore, piezoelectric phase fraction and crystallinity of PVDF-TrFE films were characterized using Fourier Transform Infrared Spectroscopy and Differential Scanning Calorimetry, respectively. All films exhibited a piezoelectric polar beta-phase formation. The crystalline beta-phase fraction of the most of the films was higher than the value of the initial material (77%). Results demonstrate the influence of solvent combinations and mixing ratios on melting temperature and crystallinity.